Non-pulsating check valve



. June 11, 1957 s. R. HIRSCH NON-PULSATING CHECK VALVE Filed March 9, 1954 IN VEN TOR.

SYLVAN RVHIRSCH' Y B 4 m w i 5 2 9 2 2 n 4 H I I. D W A G s II a 3 m El u v m m E 2 W l n a um- 3 2 I I I IHH.H.

United States 7 PatentO NON -PULSATIN G CHECK VALVE Sylvan R. Hirsch, Longmeadow,Mass., assignor to Worthington Corporation, Harrison, N. 5., a corporation of Delaware Application March 9, 1954, Serial No. 414,931

4 Claims. (Cl. 137543.13)

This invention relates to check valves and more particularly to a check valve for use in a pressure line from a pressure fluid supply source to an intermittently replenished accumulator or receiver.

In pressure fluid systems utilizing a compressor for compressing the fluid the operation of the compressor is generally controlled by a pressure switch, to stop the compressor operating motor or prime mover at a predetermined accumulator or receiver pressure and to restart the compressor upon a drop in receiver pressure below a predetermined degree.

To permit the compressor to start against no load, the fluid pressure in the discharge line between the compressor and the check valve, located in the line in advance of the receiver, is bled to atmosphere by a release valve thus unloading the compressor. The compressor is thereby allowed to restart 'free from load which would otherwise be imposed upon it by the pressure in the receiver.

A problem in such arrangements has been during receiver charging operation of the compressor, the check valve pulsates and hammers its seat eventually causing failure of the valve resulting in improper operation of the system.

The check valve of the present invention eliminates pulsation of the valve by providing a latching mechanism which holds the valve in open position .during receiver charging operation of the compressor and unlatches during periods when the compressor is stopped, thereby permitting the check valve to reseat and prevent back- .flow of pressure fluid from'thereceiver to the compressor.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a non-pulsating check valve of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings:

Figure 1 is a diagrammatic elevation of a pressure fluid system embodying the improved check valve.

Figure 2 is a vertical section through the check valve, showing the valve seated.

Figure 3 is a cross-section taken on the line 3-3 of Figure 2.

Figure 4 is a cross-section taken on the line 4-4 of Figure 2.

In Figure 1 of the drawings a fluid compressor 1, such as an air or gas compressor is operated by a prime mover 2 shown in Figure 1 of the drawings as an electric motor but it is to be understood that any suitable type of prime mover such as a gasoline engine, electric motor, etc., may be employed for operating the compressor 1. A conventional type of stop and start controller for the prime mover 2 is shown at 3, and this conventional con troller 3 is connected in an electric circuit indicated at 4 with a pressure switch 5. The pressure switch 5 may Patented June 11, 1957 be of any approved construction which may be purchased upon the open market and such pressure switches embodying a release valve, indicated at 6, are in general use in fluid pressure systems of the present type.

The discharge of the compressor 1 is connected in a pressure fluid line 7 with a receiver or accumulator 8 where the pressure'fluid is stored until it is conducted to use through any conventional type of outlet such as indicated at 9. The non-pulsating check valve 10 of the present invention is interposed in the pressure fluid line between the discharge of the compressor 1 and the receiver 8. In operation, when thepressure in the receiver 8 reaches the desired predetermined degree the pressure fluid flowing into the pressure switch 5 operates, through the electrical circuit 4, the prime mover start and stop mechanism 3, stopping operation of the compressor 1. At such time, the pressure fluid in the fluid line 7 between the compressor 1 and the check valve 1i), i. e., the upstream side of the pressure line, is bled to atmosphere through the outlet 12 of the release valve 6 and the check valve 10 acting to prevent backflow of pressure fluid from the receiver into .the upstream portion of the pressure fluid line permits the unloading of the compressor 1 and relieves it of any backflow pressure from the receiver 8 thus permitting the compressor to be restarted in a non-loading condition.

The usual type of check valve employed in the pressure fluid line pulsates during the pumping of compressed fluid fluid flow'passage therethrough comprising the upstream section 16 and the downstream section 17 which are connected through a valved port 18 surrounded by a valve seat 19. Thus when the valve 20 is seated on the valve seat 19 flow of pressure fluid through the fluid passage in the valve housing from the downstream side 17 to the upstream side 16 is prevented. The valve 20 has a valve stem 21 thereon which reciprocates in a suitable bore 22 formed in the housing 15 and a spring 23 engages the valve stem for urging the valve 20 upon its seat. During operation of the compressor the pressure of the fluid discharge by the compressor into the pressure fluid line upstream of the valve '10 is greater than the tension of the spring 23 so that such pressure will unseat the valve 20 and allow the pressure fluid to flow through the valve into the downstream side of the pressure line between the check valve 1% and the receiver 8. When the compressor is stopped the spring 23 seats the valve 20 and the pressure from the receiver 8 flowing back into the downstream section 17 assists the spring 23 in holding the valve 20 seated. The discharge flow of such reciprocating compressors is pulsating in that the compressor alternates between intake and compression actions and such pulsations would cause pulsations of the valve 20, i. e., movement of the valve oil and onto its seat resulting in the hammering of the valve on its seat and wear on both the valve and the seat if no means were provided for holding the valve open against the action of the spring 23 during the receiver charging operation of the compressor.

The valve housing 15 has a cylinder bore therein in which a plunger 26 reciprocates. The plunger 26 has a locking latch 27 thereon which extends through an opening 28 into the bore 22. The valve stem 21 isprovided with a notched or recessed portion 29 conforming to the configuration of the valve stem engaging end of the latch pin 27. A passageway 30 is formed in the valve housing which opens into the upstream side 16 of the fluid passage in the valve housing and into the cylinder 25 thus permitting pressure fluid to flow into the cylinder 25 beyond the plunger 26 and force the latch pin 27 into the notched or cutout portion 29 in the valve stem when the valve 20 is moved upwardly all its seat by discharge pressure of the compressor. So long as the pressure in the upstream side of the fluid passage is maintained, the latch pin 27 will be held in valve-holding position. As soon as the fluid pressure in the upstream side of the fluidpassage falls below apredetermined pressure a spring 31 which engages the plunger 26, will move the plunger outward and move the latch pin 27 out of engagement with the valve stem 29 allowing the valve to be seated under action of the spring 23. A second passage 32 is formed in the valve housing 15 and connects the cylinder 25 with the air releasevalve 6 through a suitable connection 33 so that when the release valve 6 is opened by action of the pressure switch the pressure behind the plunger 26 will be immediately delivered to atmosphere to permit quick movement of the plunger 26 in its unlatching operation, thus allowing the valve 20 to seat and prevent backflow of pressure fluid from the receiver 8 to the compressor 1 when the compressor is stopped.

If it is so desired, a vent passage 34 may be provided in the housing for permitting release of any pressure fluid which may leak into the cylinder 25 on the inner side of the plunger 26 to be vented to atmosphere. Suitable sealing rings 35 may be provided on the latch pin 27 and plunger 26 to prevent leakage of pressure fluid across these elements.

It willbe understood that the invention is not to be limited to the specific constructionor arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is: t

1. In a check valve comprising a valve body. having an inlet and an outlet passage therein for passing fluid under pressure therethrough,a valve seat in said body having a port'in communication with said inlet and outlet passages, a valve disc adapted to seat against said valve seat to cover said port and control the flow of fluid therethrough, said disc adapted to unseat from said valve seat to open said port when the fluid pressure in the inlet, passage exceeds the fluid pressure in the outlet passage, tension means adapted to reseat the disc on the valve seat to close the port when the fluid pressure in the inlet passage decreases belowthe fluid pressure in said outlet passage, a valve stem connected to said disc having a circumferential recess therein, a cylinder in said body having a plunger disposed for slidable movement therein, a latch pinconnected to said plunger adapted to extend into said recess, a fluid supplyline in communication with said inlet passage and one end of said cylinder to supply fluid under pressure to said cylinder to move said plunger in the cylinder to position said latch pin in said recess to hold the disc in an unseated position, and spring means adapted to move said latch pin out of said recess to release said disc when the pressure in said fluid supply passage decreases below a predetermined value.

2. In an automatic locking and unlocking device for a check valve including, a valve disc for controlling the flow of fluid therethrough, a disc stem having a notch therein connected to the valve disc, and a first tension means for maintaining the valve disc normally seated, said locking and unlockingdevice comprising latching means disposed in the check valve transversely of the longitudinal axis ofthe disc stem and adapted to engage with the disc stem notch :when the valve disc is unseated, a second tension means coacting with the latching means to normally prevent said engagement, and a conduit connected to transmit the pressure of fluid flowing to the valve disc to the said latching means whereby when the pressure of the said flowing fluid exceeds a predetermined value the valve disc is unseated and the latching means urged into engagement with the disc stem notch to hold the valve disc in the unseated position, and when the fluid pressure subsequently decreases below a predetermined value the second tension means disengages the latching means and the valve disc is returned to the,

thereof, said controlled vent port opening when the fluid pressure decreases below a predetermined value.

References Cited in the file of this patent UNITED STATES PATENTS 761,183 Sartain May 31, 1904 1,695,978 Redfield Dec. 18, 1928 1,719,678 Swearingen July 2, 1929 1,817,698 McMillan Aug. 4, 1931 2,231,904 Gustafson Feb. 18, 1941 FOREIGN PATENTS 496,454 Germany Apr. 23, 1930 

